WO2010076113A1 - Oscillation drive - Google Patents

Abstract

The invention relates to an oscillation drive (1), especially for motor vehicle applications, comprising a drive element (2) that can be actuated to oscillations by means of at least one actuator (3, 4), which is in driving arrangement and design to the output element (5). According to the invention, there is a spring-mounted counter-mass (11) that applies force to the output element (5) in the direction of the drive element (2).

Description

 description

vibration drive

State of the art

The invention relates to a vibration drive, in particular for motor vehicle applications, preferably for adjusting a motor vehicle window, according to the preamble of claim 1.

From EP 01 55 694 A2 trained as a linear drive vibration drive is known. The vibration drive designed as a ram drive comprises two piezoelectric actuators arranged at an angle to one another, with which a drive element (plunger) can be excited to oscillate in order to drive a rail (driven element) in translation. The drive element is pressed by means of a spring in a pressing direction against the driven element in order to guarantee a sufficient force transmission by frictional engagement.

Disclosure of the invention

The invention has for its object to provide a vibration drive with improved efficiency.

This object is achieved with a vibration drive with the features of claim 1. Advantageous developments of the invention are specified in the dependent claims. All combinations of at least two features disclosed in the description, the claims and / or the figures fall within the scope of the invention.

The invention is based on the idea of assigning a countermass to the output element of at least one actuator, preferably a piezoactuator, that can be excited to oscillate in vibrations, and to store these resiliently in such a way that this force is applied to the driven element driven by the drive element in the direction of the output element. In other words, a counterweight that can be excited to oscillate, preferably indirectly via the output element, is provided, which ensures that the output element is pressed against the drive element, that is, that contact forces act between the drive element and the driven element. If necessary, can be dispensed with a separate Federkraftbeaufschlagung of the drive element in the direction of the output element, as provided in the prior art. However, it is also possible to provide such a resilient mounting of the output element in addition to the at least one spring-mounted counterweight. By providing a swinging or swingably arranged counterweight, the force balance is dynamically increased to the output element by the contact forces of the counterweight. In this way, a reduction of the force amplitude of the drive element can be achieved with constant effective output forces, resulting in an increase in the overall efficiency of the

Vibration drive leads.

An embodiment of the vibration drive in which the countermass to the drive element performs an opposite phase oscillation is very particularly preferred. In other words, the counterweight oscillates in development of the invention in a counter-resonance to the drive element, thereby further increasing the balance of power on the output element.

In a further development of the invention is advantageously provided that the at least one drive element and the at least one counterweight are arranged on two opposite sides of the driven element, so that the drive element, a second side facing away from the first side of the power take-off element and the counterweight.

Ideally, the oscillating drive provided with the oscillating counterweight is designed as a linear drive, wherein in this case the output element is preferably designed as a rail with which an object to be driven translationally, preferably a motor vehicle window pane, is coupled. In this example, the drive element engages an upper side of the rail and the counterweight on the underside of the rail. Most preferably, counterweight and drive element are directly opposite, ie an imaginary, perpendicular to the output element axis intersects both the output element and the counterweight.

Particularly preferred is an embodiment of the vibration drive, in which the counterweight spring-mounted spring is designed such that this in the normal direction relative to the driven element has a higher rigidity than in the tangential direction, i. as in the direction of movement of the output element. In this way it can be achieved that hardly tangential forces result on an optionally provided bearing, which will be explained later on, for rotatably supporting the counterweight, thereby avoiding tilting of the counterweight.

With regard to the specific design of at least one, preferably only one, spring for resilient mounting of the counterweight, there are different possibilities. According to a first alternative, a plate spring is used for supporting the counterweight, which is further preferably provided with a plurality of radial slots distributed over the inner circumference. The use of a disc spring makes it possible to realize a high level of normal rigidity in a simple manner. The required (low) tangential rigidity can be realized by means of a guide of the actual bearing for rotatably supporting the countermass. Preferably, the assembly takes place in the untensioned state of the plate spring, wherein the bias voltage at the end of the assembly, for example, by tightening an adjusting screw (clamping screw) is adjusted. Preferably, the plate spring is designed such that a plateau, i. a horizontal one

Flat section in the curve is created, whereby the assembly is further simplified and the spring force can be adjusted in a simplified manner, since the system can be brought to a high biasing force with just a few screw turns. When the spring characteristic plateau is reached, only a slight increase in the prestressing force takes place when the screw is turned around again, which is a

Fine adjustment possible. In this way, space can be saved and simplify the assembly or setting process.

According to a second alternative, the spring for resiliently supporting the countermass can be formed as an at least approximately C- or U-shaped contoured spring, in particular spring-loaded spring. With a thus formed spring a particularly high normal stiffness and at the same time a low tangential stiffness can be realized.

In a further development of the invention is advantageously provided that the contact pressure with which the counterweight presses against the driven element, is adjustable. This is preferably done by adjusting the spring force of the countermass bearing spring, which in turn very particularly preferably can be achieved via at least one spring clamping element, which in the case of execution of the spring as a plate spring, for example with a spring passing through the clamping screw can be achieved. In the case of realization of a C- or U-shaped spring, the two at least approximately parallel legs of the spring can be transversely to their longitudinal extent, i. towards each other, are stretched by means of a suitable spring tensioning element until the desired spring force and thus the desired contact pressure is set.

As already indicated above, it is particularly preferred, but not mandatory, for the counterweight to be rotatably supported, particularly preferably by means of a roller bearing, for further optimization of the efficiency of the vibration drive. It is further preferred if the counterweight is formed as a hollow cylinder, which is penetrated by a corresponding bearing axis.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings.

These show in:

1 shows a schematic representation of a first embodiment of a

Vibration drive with oscillating counterweight, wherein for the resilient mounting of the counterweight a substantially

C-shaped contoured band spring is provided, 2a and 2b show different views of an alternative embodiment of a vibration drive, wherein, in contrast to the embodiment shown in FIG. 1, a spring tensioning element for adjusting the

Contact force of the counter element is provided

FIGS. 3a and 3b show different views of a further alternative exemplary embodiment of a vibration drive, wherein the resilient mounting of the

Counterweight a disc spring is provided

4 shows a preferred spring characteristic of a spring provided for the resilient mounting of the counter element,

5a to 5f: a first vibration cycle in an embodiment in which the counterweight lifts off from the driven element in its vibration, and

Fig. 6a to 6f: an alternative vibration cycle with permanently on the output element adjacent counterweight.

In the figures, like elements and elements are denoted by the same function and the same reference numerals.

In Fig. 1 designed as a linear drive for adjusting a motor vehicle window not shown vibratory drive 1 is shown. In the exemplary embodiment shown, it is a piezomotor, which alternatively can also be realized, for example, as an ultrasonic motor. The vibration drive 1 is designed as a so-called ram drive and comprises a shock-shaped drive element 2, which by means of two, designed as piezoelectric actuators, actuators 3, 4 to a trained as a rail output element 5 (runner) driving vibration can be excited. At the point in the arrow 6 translationally adjustable output element 5, the aforementioned motor vehicle window is set in a suitable manner.

As is further apparent from FIG. 1, the piezoelectric actuators 3, 4 are coupled to the drive element 2 via a metallic bridge part 7. If necessary, a drive element 2 or the drive means 8 formed by the actuators 3, 4, the bridge part 7 and the drive element 2 can be provided in the direction of the output element 5 spring-loading spring 12.

As is apparent from Fig. 1 further, the drive element 2 is located on a first side 9 of the output element 5, so that the first side 9 is subjected to force by the drive element 2 in its oscillating motion, resulting in the translational adjustment of the output element 5 with object fixed thereto , here a motor vehicle window pane (not shown), results. On the side facing away from the first side 9 second side 10 of the output element 5, which runs parallel to the first side 9, a swinging counterweight 1 1 is arranged. Thus, the counterweight 1 1 can oscillate horizontally to the surface extension or to the direction of movement of the output element 5, this is resiliently mounted - in the illustrated embodiment with a substantially U-shaped spring 12 in the region of the output member 5 facing apex 13 a bearing axis 14 receiving dent or indentation 15 has. The bearing axis 14 passes through the hollow-cylindrical counterweight 1 1 transversely to the possible adjustment directions of the output element 5, which are indicated by the arrows 6, and serves to rotatably support the counterweight 1 1. The spring 12 allows swinging of the counterweight

1 1 in a normal direction relative to the output element. 5

As is further apparent from Fig. 1, are the drive element 2 and the counterweight 1 1 on an imaginary axis 16 which intersects the surface extension of the output element 5 perpendicular. Also the axis 16 to the rotatable

Bearing the counterweight 1 1 is located on this axis 16. The counterweight 1 1 is mounted rotatably relative to the axis 16 by means of a rolling bearing, not shown.

The bearing of the counterweight 1 1 is designed such that the counterweight 1 1 in operation, ie during the operating frequency of the vibration drive 1, ge Duration of the drive means 8, in opposite phase to the drive means 8 and the drive element 2 oscillates, whereby the force balance on the output element 5 and the contact forces of the counterweight 1 1 - in comparison to the prior art - increases.

5a to 5f, a vibration cycle of a first embodiment is shown, wherein the resilient mounting of the counterweight 1 1, which was not shown for reasons of clarity in Figs. 5a to 5f, is designed such that the counterweight in the normal direction of the driven element 5 and turn against it again.

In an alternative vibration cycle of an alternative vibration drive 1, the spring force for the counterweight 1 1 is set such that the counterweight in their vibration not, or only slightly, from the output element 5 lifts in the normal direction.

In FIGS. 5 a to 6f, pressure or contact forces are shown with hollow arrows 17 with which the drive element 2 and / or the counterweight 1 1 press against the output element 5. A hollow circle 21 identifies the situations or oscillation states at which this force / forces is / are zero.

The full arrows 18 indicate the adjustment speed or the adjustment in which the drive element 2 and / or the counterweight 1 1 moves / move at the appropriate time. The full circles 20 symbolize a zero adjustment speed. On the output element 5 is a rectangular

Distance marking 19 shown to visualize the relative movement of the output element 5 relative to the drive element 2 to the counterweight 1 1.

The exemplary embodiment illustrated in FIGS. 2 a and 2 b essentially corresponds to the exemplary embodiment illustrated in FIG. 1, so that in order to avoid repetition, the following will essentially deal only with the differences from the exemplary embodiment described above. With regard to the similarities, reference is made to the preceding description of the figures. As can be seen from a combination of FIGS. 2a and 2b, the C-shaped spring 12 can be tensioned. For this purpose, a spring tensioning element 22 is provided, with which the two at least approximately parallel legs 23, 24 to each other are kraftbeaufschlagbar, so as to adjust the spring force. Preferably, the spring tensioning element 22 comprises a screw 25 for adjusting the spring force and thus the contact pressure with which the counterweight 1 1, the output element 5 subjected to force. From Fig. 2b, a substantially U-shaped contoured profile frame 26 is shown, on which the actuators 3, 4 and the spring 12 are fixed.

A further alternative exemplary embodiment of a vibration drive 1 is shown in FIGS. 3a and 3b. Instead of a C-shaped contoured band spring (spring 12) designed as a plate spring spring 12 is provided. The plate spring 12 is arranged such that the conically opening side of the plate spring 12 in the direction of rail-shaped output element 5 shows. On the spring 12, in turn, a bearing holder 28 is mounted, which carries the bearing axis 14 for rotatably supporting the counterweight 1 1. As is apparent from Fig. 3b, the spring force of the spring 12 and thus the contact pressure with which the oscillating

Counterweight 1 1 is pressed against the output element 5, set by means of a screw 25 (clamping screw) comprehensive spring tensioning element 22, which passes through the spring 12 in the normal direction relative to the output element 5 and with the provided with an internal thread bearing bracket 28 in the direction of a screw head 27 of the screw 25 is movable, so as to tension the spring formed as a plate spring 12.

The embodiment shown in FIGS. 3a and 3b is also operable in the different operating modes, which are dependent on the spring tension and are shown in FIGS. 5a to 5f and FIGS. 6a to 6f.

In Fig. 4 is a schematic diagram of a spring characteristic of a preferred, used for use spring 12 is shown. This comprises a (middle) plateau section 29, in which the spring force F _F does not increase or increases only slightly with the spring travel s.

Claims

claims 1 . Vibration drive, in particular for motor vehicle applications, comprising a drive element (2) which can be excited into vibrations by means of at least one actuator (3, 4), which drive element is arranged and designed to drive, characterized, in that a force-absorbing counterweight (1 1) which acts on the output element (5) in the direction of the drive element (2) is provided. 2. Vibration drive according to claim 1, characterized in that the bearing of the counterweight (1 1) is designed such that the GE genmasse (1 1) in opposite phase to the drive element (2) oscillates. 3. Vibration drive according to one of claims 1 or 2, characterized in that the drive element (2) with a first side (9) of the driven element (5) and the counterweight (1 1) with one of the first side (9) remote from the second side (10) of the output element (5) cooperates. 4. Vibration drive according to one of the preceding claims, characterized in that the vibration drive (1) is designed as a linear drive or as a rotary drive. 5. Vibration drive according to one of the preceding claims, characterized in that the counterweight (1 1) and the drive element (2) on a common seeds, imaginary, perpendicular to the surface extension of the drive element (2) arranged axis (16) are arranged. 6. Vibration drive according to one of the preceding claims, characterized in that as spring (12) for resilient mounting of the counterweight (1 1) a spring (12) is provided, which is perpendicular to the direction of movement of the output element (5) stiffer than in the direction of movement , 7. Vibration drive according to one of the preceding claims, characterized in that as a spring (12) for resilient mounting of the counterweight (1 1) a plate spring is provided. 8. Vibration drive according to one of claims 1 to 6, characterized in that as spring (12) for resilient mounting of the counterweight (1 1), at least approximately C or U-shaped spring (12) is provided. 9. Vibration drive according to one of the preceding claims, characterized in that the contact pressure with which the counterweight (1 1), the output element (5) acted upon, is adjustable. 10. Vibration drive according to one of the preceding claims, characterized in that the, preferably cylindrical, counterweight (1 1) rotatable, in particular by means of a rolling bearing or not rotatable by means of a sliding bearing, is mounted.